Style the :command: role and similar

[webknjaz]

I've been using more semantic roles from https://www.sphinx-doc.org/en/master/usage/restructuredtext/roles.html#role-command and noticed they aren't distinguishable from generic inline highlighting.
So I propose improving the look for things like :command:, :program:, :envvar: and others.

[webknjaz]

@pradyunsg ^

[pradyunsg]

ACK, this has to wait until I'm married. 😅

[webknjaz]

Yeah, when I posted the comment I wished there was a way to schedule it for later like in signal/slack/email :)

[webknjaz]

@him2him2 would you like to tackle this?

[him2him2]

Hey @webknjaz, I took a first pass at this: #924

Let me know if it's along the lines of what you were looking for, or if you'd like anything adjusted.